[Bug c++/59081] New: GCC should forbid using a private member datatype in template class

["romain.geissler at gmail dot com" <gcc-bugzilla@gcc.gnu.org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59081

            Bug ID: 59081
           Summary: GCC should forbid using a private member datatype in
                    template class
           Product: gcc
           Version: 4.8.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: romain.geissler at gmail dot com

Hi,

GCC should emit an error in the C class when referencing A::B in the following
code (as clang does).

class A{
    private:
        struct B{} _b;
};

template <typename T> class C{
    public:
        A::B* _b;
};

C<void> c;

Tested with gcc 4.8.2 and also the latest 4.9.0 trunk:

Using built-in specs.
COLLECT_GCC=/remote/intdeliv/seidelde/local/gcc/bin/../latest/bin/g++
COLLECT_LTO_WRAPPER=/remote/intdeliv/seidelde/local/gcc/4.8.2/libexec/gcc/x86_64-unknown-linux-gnu/4.8.2/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with: ../gcc-sources/configure --prefix
/remote/intdeliv/seidelde/local/gcc/4.8.2
--with-gmp=/remote/intdeliv/seidelde/local/gmp/5.1.3
--with-mpfr=/remote/intdeliv/seidelde/local/mpfr/3.1.2
--with-mpc=/remote/intdeliv/seidelde/local/mpc/1.0.1 --enable-lto
--disable-multilib --enable-languages=c,c++
Thread model: posix
gcc version 4.8.2 (GCC) 


With clang I got the expected behavior:

rgeissler@ncegcolnx273:/tmp> ~seidelde/local/clang/bin/clang++ -c test.cpp
test.cpp:8:12: error: 'B' is a private member of 'A'
        A::B* _b;
           ^
test.cpp:3:16: note: declared private here
        struct B{} _b;
               ^
1 error generated.

Cheers,
Romain